David Taplin

Aging, Acculturation, Salt Intake, and Hypertension in the Kuna of Panama

The indigenous Kuna who live on islands in the Panamanian Caribbean were among the first communities described with little age-related rise in blood pressure or hypertension. Our goals in this study were to ascertain whether isolated island-dwelling Kuna continue to show this pattern, whether migration to Panama City and its environs changed the patterns, and whether the island-dwelling Kuna have maintained their normal blood pressure levels despite partial acculturation, reflected in an increased salt intake. We enrolled 316 Kuna participants who ranged in age from 18 to 82 years. In 50, homogeneity was confirmed by documentation of an O+ blood group. In 92 island dwellers, diastolic hypertension was not identified and blood pressure levels were as low in volunteers over 60 years of age as in those between 20 and 30 years of age. In Panama City, conversely, hypertension prevalence was 10.7% and exceeded 45% in those over 60 years of age (P < .01), blood pressure levels were higher in the elderly, and there was a statistically significant positive relationship between age and blood pressure (P < .01). In Kuna Nega, a Panama City suburb designed to maintain a traditional Kuna lifestyle but with access to the city, all findings were intermediate. Sodium intake and excretion assessed in 50 island-dwelling Kuna averaged 135 +/- 15 mEq/g creatinine per 24 hours, exceeding substantially other communities free of hypertension and an age-related rise in blood pressure. Despite partial acculturation, the island-dwelling Kuna Indians are protected from hypertension and thus provide an attractive population for examining alternative mechanisms.

Community control of scabies: a model based on use of permethrin cream

For 18 years treatment with lindane or crotamiton products has failed to stem the epidemic of scabies among the Kuna Indians in the San Blas islands of the Republic of Panama. Permethrin 5% cream was introduced as the only treatment in a programme to control scabies on an island of 756 inhabitants and involving workers recruited locally. Prevalence fell from 33% to less than 1% after every person was treated. As long as continued surveillance and treatment of newly introduced cases was maintained, prevalence of scabies remained below 1.5% for over 3 years. When supply of medication was interrupted for 3 weeks, prevalence rose to 3.6%. When control was lost after the US invasion of Panama, prevalence rose to 12% within 3 months. Bacterial skin infections decreased dramatically when scabies was controlled. Permethrin is safe and effective even in areas where this disease has become resistant to lindane.

Comparison of crotamiton 10% cream (Eurax) and permethrin 5% cream (Elimite) for the treatment of scabies in children.

Permethrin 5% cream (Elimite) was approved as a treatment for scabies by the U.S. Food and Drug Administration in September 1989. in a doubie‐biinded, randomized study, it was compared with crotamiton 10% cream (Eurax) for the treatment of scabies in children 2 months to 5 years of age. Two weeks after a singie overnight treatment, 14 (30%) of 47 chiidren were cured with permethrin 5% cream, in contrast to oniy 6 of 47 (13%) of subjects treated with Eurax. Four weeks after treatment the figures were 89% and 60% cured for the two agents, respectively. In 10 of the 19 patients whose treatment failed, the condition became worse after therapy. The difference in efficacy in favor of permethrin was significant (P = 0.002). That agent also demonstrated greater effectiveness in reducing pruritus and secondary bacterial infections. Eilmite offers a safe, efficacious, and cosmetically elegant aiternative to Eurax in the treatment of scabies in chiidren.

PREVALENCE OF STREPTOCOCCAL PYODERMA IN RELATION TO CLIMATE AND HYGIENE

Abstract Skin infections in Colombia were Summary studied over one month to determine the effect of climate on the prevalence and flora of bacterial pyoderma, and to acquire first-hand information on cutaneous infections of military importance in tropical Latin America. The survey involved nearly 1500 people (children and soldiers) living in four ecological zones, ranging from the cool climate of Bogota to a jungle environment. Prevalence of pyoderma and rates of recovery of bacterial pathogens were highest in the jungle, intermediate in the temperate zone, and lowest in the cool climate. The level of hygiene was the principal determinant of prevalence within each climatic zone. Streptococcus pyogenes was recovered from 82% and Staphylococcus aureus from 76% of all lesions cultured. Soldiers in the jungle had the highest prevalence of pyoderma (38%), whereas those in the dry tropics (savanna) had a low prevalence of pyoderma.

Permethrin 5% dermal cream: A new treatment far scabies

Permethrin 5% dermal cream (Burroughs Wellcome Co.) was compared in an investigator-blinded, randomized study against lindane 1% lotion (Kwell) for the treatment of microscopically confirmed scabies. Eleven of twenty-three patients treated with permethrin cream were cured in 2 weeks (48%). Only two patients had scabies 1 month following a single treatment with this product, giving a cure rate of 91%. One of these two patients was considered to have a reinfestation. Only three of twenty-three (13%) patients treated with 1% lindane lotion (Kwell) were free of scabies 2 weeks after a single treatment and fifteen of twenty-three (65%) were cured at 1 month. The unusually high percentage of treatment failures (35%) following lindane therapy may have been related to extensive use of this agent for head lice and scabies in this village during the preceding 5 years. The higher cure rate at 1 month seen with permethrin cream was significant (p less than 0.025). Permethrin 5% dermal cream offers a new, cosmetically elegant alternative to lindane therapy and was effective in a community in which lindane demonstrated an unacceptable level of treatment failures.

Permethrin 1% Creme Rinse for the Treatment of Pediculus humanus var capitis Infestation

Abstract: Permethrin 1% creme rinse (NIX) was tested as a treatment for Pediculus humanus var capitis (head lice) in a placebo‐controlled, double‐blinded, randomized study. As a positive control, a third arm of the study included nonrandomized, but investigator‐blinded, treatment with 1% lindane shampoo (Kwell). At 14 days after treatment, 97% of patients treated with permethrin were free of lice compared to 6% of placebo‐treated patients (P < 0.001) and 43% of the lindane‐treated group. Permethrin was 70% ovicidal compared to 14% for placebo (P< 0.001) and 45% for lindane. No adverse experiences were noted during this study. Permethrin 1% demonstrated high pediculicidal and ovicidal activities, which in combination with its low mammalian toxicity, residual activity, and cosmetic properties, make it an excellent treatment for pediculosis capitis.

A comparative trial of three treatment schedules for the eradication of scabies.

A trial of three treatment schedules, consisting of 1% gamma benzene hexachloride (GBH) lotion applied head to toe and left on the body for 2, 6, or 12 to 24 hours was conducted on an island of 2,076 persons, approximately 70% of whom had clinical evidence of scabies. The island is situated off the north coast of the Republic of Panama. Examination at 1 month after therapy showed that both the 6-hour and 12- to 24-hour cure rate was high (96% and 98%). There was a significantly lower cure rate in the 2-hour group, in which only 82% were cured. Eleven to twelve percent of the subjects became infested in all groups, presumably due to contact with untreated persons with scabies on the island. A single 6-hour application of 1% GBH lotion appears to be adequate therapy for scabies if properly applied. The entire population at risk should be treated at the same time if possible to reduce or eliminate the risk of infestation. No adverse reactions to 1% GBH lotion were observed.

Sodium channel mutations associated with knockdown resistance in the human head louse, Pediculus capitis (De Geer)

Pyrethroid resistance in human head louse populations is widespread in the United States and worldwide. We previously documented that the knockdown resistance of permethrin-resistant head louse populations is associated with the T929I and L932F (T917I and L920F in the numbering of the louse amino acid sequence) mutations in the voltage-sensitive sodium channel α-subunit gene. In order to identify additional sodium channel mutations potentially associated with knockdown resistance, we cloned and sequenced full-length cDNA fragments from insecticide-susceptible (Ecuador) and permethrin-resistant (Florida) head louse populations and from an insecticide-susceptible body louse population (Israel). Sequence comparisons of the complete open reading frames of the sodium channel genes identified one additional novel mutation (M815I), which was located in the IIS1-2 extracellular loop of the α-subunit, from the permethrin-resistant head louse population. Absolute conservation of the Met815 residue at the corresponding positions within sodium channels from all known susceptible populations of insect species implied that the M815I mutation likely has a functional significance in resistance. Sequence analyses of cloned cDNA fragments and genomic DNA fragments from individual louse samples, both containing the three mutation sites, confirmed that all the mutations exist en bloc as a haplotype. Northern blot analysis identified a single 7.2 kb transcript. The comparison of complete open reading frame sequences (6156 bp) of sodium channel gene between head and body lice revealed 26 polymorphic nucleotides, of which only one resulted in a conservative amino acid substitution (glutamic versus aspartic acid at 11th amino acid position). The virtual identity in nucleotide sequences indicated that both body and head lice are conspecific, and lends justification of the use of the body louse as a surrogate organism for the head louse in biochemical and molecular biology studies. Conserved point mutations resulting in knockdown resistance to the pyrethrins, the pyrethroids, and DDT are suitable for detection by various DNA-diagnostic protocols for monitoring and resistance management.

Foot lesions associated with Pseudomonas cepacia

Summary Pseudomonas cepacia was isolated in small numbers from swamp waters and in large numbers from the toewebs of troops after training in swamp conditions. Colonisation with P. cepacia was associated with macerated, hyperkeratotic lesions of the feet. The isolates showed resistance to a wide range of antibiotics, but strains from these and other sources were sensitive in vitro to trimethoprim and sulphamethoxazole. The ability of P. cepacia to colonise sodden but otherwise intact skin is significant in view of the organisms potential as a cause of wound and other infections.

Isolation, Amplification, and Sequencing of Human Mitochondrial DNA Obtained from Human Crab Louse, Pthirus Pubis (L.), Blood Meals

The ability to identify individual human hosts based on analyses of blood recovered from the digestive tract of hematophagous arthropods has been a long-term pursuit in both medical and forensic entomology. Blood meal individualization techniques can bring important advancements to studies of vector-borne disease epidemiology. Forensically, these analyses may aid in assailant identification in violent crime cases where blood-feeding insects or their excreta are recovered from victims or at crime scenes. Successful isolation, amplification, and sequencing of human mitochondrial DNA obtained from adult human crab lice fed on human volunteers are reported. Adult lice were removed from recruited volunteers frequenting inner city health clinics. Live lice were killed by freezing and subsequently air dried at ambient temperature. A saliva sample was obtained from each volunteer and served as a DNA reference sample. Volunteers were afforded free, approved pediculosis treatment. Individual lice were subsequently processed using procedures developed for the extraction of mitochondrial DNA from human hair, teeth, and bone. The resulting DNA was amplified by the polymerase chain reaction and sequenced. Our results point to valuable avenues for future entomological research.